Treatment of titanium-bearing materials



May 26, 1936.l s. s, svENDsEN 2,042,435

TREATMENT OF TITANIUM BEARING MATERIALS Filed Sept. 27, 1934 2Sheets-Sheet 1 fwd/afar Y p "k1 fifa/gew@ May 26, 1936- s. s. svENDsEN2,042,435

TREATMENT OF' TITANUM BEARING MATERIALS Filed Sept. 27, 1934 2Sheets-Sheet fnyeraifar' @end/Siam@ Patented May 26, y1936 UNITED STATESTREATIWENT l0F TITANIUM-BEARING MATERIALS Vsve'mi s. svenasen, Madison,wis., assignor, by mesne assignments, to Burgess Titanium Company, acorporation of Delaware v Application sgtember 27, i934, lsei-iai No.745,753

45 Claims. {I'his invention relates to improvements in the production oftitanium oxide from titanium-conmaterials, particularly titanium oxideminerals or compounds such as ilmenite and 54 rutile; by processeswherein the titanium of such compounds is'converted into tetrauorldecompounds, as more fully hereinafter set forth. This invention relatesin part-to improvements in the processes described and claimed in mycopending l application No. 614,043, ledMay 27, 1932, oi which thisapplication is a continuation in part. In the process of the presentinvention, the titanium content of the ore is secured in the form offluorideJ compounds soluble in aqueous i liquids, particularly of anon-alkaline character', the compounds beingsuch that the titanium'maybe readily separated from their solutions in highly purified form,either as hydrates or as compounds readily convertible into hydrates.The hydrates thus secured are of high purity and of a character suchthat they are readily adaptable to the production of pigmentsv or othermaterial u wherein freedom from extraneous compounds is essential. Intthe production of the soluble fluoride compounds from thetitanium-bearing materials or ores, their formation and solution may beeffected simultaneously, the resulting solution being separated from theresidue; or soluble fluoride coml pounds may be formed by reaction ofthe titanium ore'and subsequently dissolved and removed therefrom by avsuitable solvent; or the soluble fluoride compounds maybe formed andremoved from 'the remaining constituents of the ore by volatiliaationfor subsequent solution. In each case the soluble compounds Lformed aretetrafluoride com-` pounds of ammonia and titanium and the resultingsolutions have similar characteristics. However, with eachcalconipdsition and physical character of the-soluble tetraiiuoridecompound formed may vary,

Veach having certain advantages under different l variation of theprocedure in ac-Y lU cordance with-the invention, Ythe specific chemi-(Cl. 23-202) f compound ar'deeomposed by water, part ofv the vsiliconbeing thereby precipitated as the hydrate. All of the siliconlsvcompletely precipitated by the addition of a stoichiometricallyequivalent amount of ammonia. In comparison the corresponding 5 titaniumcompounds are water-soluble without decomposition under ordinaryconditions and theV titania may be precipitated completely therefrom onthe addition of an excess of ammonia.

In' operating in accordance withthe present 1o invention, the conversionof the titanium content of the titanium-containing material, such astitanium oxide ore, into the desired tetra-uoride compound ,is effectedby subjecting it to the action of a reactive flurdecompound, preferablyVan ammonium fluoride, suitably after 'ine grinding and under conditionsas hereinafter set forth. The reaction'ofl the reactive ammoniumViiu'oride compound on the titanium material in accordance with thepresent invention results in the formation of certain ti um-ammoniumuoride compounds. 'I'hese y be either water-soluble primary compounds ormore complex compounds, depending upon the conditions obtaining duringreaction. 25

In carrying out the presentv invention, I have found it desirable to addammonium fluoride to the titanium oxide compound in excess of theVquantity theoretically required byv stoichiometrical calculation forthecomplete 4.conversion of 30 the material into simple uorldesto'secure` a Vhigh yieldof theV primary compound referred to. Fo r\ finstance,V for one molecule of titanium oxide (T102) 4 molecules ofammonium uoride are required stoichiometrically as shownv in Equation(l) but I prefer to employ at least 6 molecules of ammonium fluoride andin general considerably more:

` The reaction may be carried out in the presence of water and with alarge excess of ammonium uoride, in which case'anammonium-titaniumuorine compound, which may bea double fiuoride oftitanium and ammonium or possibly a titanofluoride, is formed. Whileless of the ufide may bey used, the large excess of fluoride isdesirable in orderto secure complete reaction. Thus, if onlystoichiometric proportions are used, a p art of the oxide remainsunattacked. The exact composition ofthe double fluoride is in doubt. Ifthe reaction is carried outin the dry way, that is, if substantially dryammonium fluoride is mixed with a ground titanium oxide and heated tothe 'reaction temperature, suitably below 55 f yaporization starting at15o-206 temperature of C. .and usually at '75, -150 ,C., or at a 110 andhigher so that the presence of liquid water is substantially o r comvpletely prevented, the reaction products are different incomposition inthat the ammonia formed unites with the double fluoride of titanium andammonia to form a vaporizable complex ammino compound. When 6 or moremolecular parts of ammonium uoride are used the reaction (in the dryway) appears to be about as follows:

The reactions in both the wet and dry way are more readily carried outwhen ilmenite is used than when rutile is used. Possibly the iron oxidein the ilmenite or the iron iiuoride formed by the reaction acts in someway-to facilitate the reaction. Certain aspects of the reaction in thedry way are set forth and claimed in my prior application Serial No.614,043.

'I'he complex titanium-tetrauoride compound formed in accordance withEquation (2) at reaction temperature below 150-200 C., is not de'-composed by Water'vapors at a temperaturexsubstantially below itsvaporization temperature. It provides a ready means for separation oftitanium from a reaction mixture, for example,'by vaporization, in whichcase there is accompanying dissociation. -On heating to above 150-200 C.

' dissociation starts and some ofthe ammonium fluoride is driven fromthe complex titanium salt. However, this dissociation of the ammoniumfluoride from the complex compound is not completeuntil the complexcompound vaporizes, such about 290-300 C. On dissociation of thecomplexcompound, the titanium is in the form of vapors of titaniumtetrafluoride compounds, principally of the diammino- When ammoniumfluoride solution is leaching, it is preferably of the concentrationshereinafterspeciiied, since the solubility of ferrous fluoride, whichmay be present, varies inversely with the concentration of the ammoniumfluoride, being many times more soluble in water than in a 20% NHiFsolution. An adequate excess quantity of ammonium fluoride is desirable.When the reaction is carried out in the dry way and'ammonium Yiduorideis added to the titanium oxide compound in stoichiometric'pro portionsaccording to Equation (1), there is a shortage of reactive fluoridecaused by formation of the complex titanium tetrafluoride compound ofEquation (2) wherein a: and y are each at least 2'. Some ammoniumfluoride may be Volatilized before it reacts with thetitaniumrcontaining mav terial if the stoichiometric proportion isinitially supplied in accordance with'l Equation (l) 'or (2) and thisvolatilization loss also makes advisable the use of additional excessfluoride. Further-' more, in the primary decomposition reaction, mereacttallic oxides other than titanium may also with the ammonium fluoride,as for example, the iron oxide in ilmenite. The iron oxide-reacts toform iron fluoride which combines to form a douduced or finely groundfluorspar.

A leaching ble salt pvith excess ammonium fluoride, 4 molecules ofammonium uoride being theoretically necessary in the reaction for eachmolecule of iron oxide figured as FeO. The complete reaction v withilmenite is probably as shown by the fol- 5 lowing equation (in the dryway):

(3') TiOzFeO+10NH4F= A Y '1iF4xNH:.uNH4+FeFz.2NI-I4E+3H2O+ a l(6-z)NH:+(2-11)NH4F lo (a: and u probably being 2 or more). Thecomposition of ilmenite given above is merely illus-v trative astheriitio` of iron oxide to titanium'oxide Y varies considerably.

Preferably, substantially more than 10 molecular partsA ofl theammoniumv fluoride are used. in reaction with ilmenite because a portionof the ammonium vfluoride vaporizes during the course ofthe reaction,especially if the temperature isabove 150 C. Above this temperature theammonium fluoride has an appreciable vapor pressure.: It melts and boilsat about 200 C. or slightly threabove. Excessv fluoride is notdetrimental to the reaction.l If caking of the charge occurs in thefurnace this may be prevented by mixing an-inert material with it. Aconvenient inert material is the residual iron fluoride pro- The finelyground titanium-containing material and excess of ammonium fluoride aremixed thoroughly and heated, suitably in an iron container andpreferably with constant stirring to prevent local overheating and tosecure more When ilmenite is used vthere may be some reaction at roomtemperature but the :temperature is raised to above '15 C. and pref-'-erably above C.110 C. to complete the primary decomposition reactionquickly and emciently. .Although the temperature of the re'- action massmay be raised to 290 C.300 C. for 40 the primary reaction it preferablyisv kept belowl about 220 C. and usually at about 150 .C. at whichtemperature' the reaction is vigorous. When ilmenite is used there issome tendency to fuse if thetemper'ature of the reaction mass is 45allowed to go above`" to 150 C. during the early stages of the reaction.At later stages, the temperature employed may be higher.

Rutile does not react appreciably with ammonium fluoride under about'140C. but the re- 50 reaction under these conditions takes place in what Idesignate as a substantially dry state; that is, inthe 4absence ofliquid water.

The ammonium fluoride and titanium-bearingt material may be supplied inthe reaction in a variety of ways to secure the best resultsvwith' thes'peciiic ore employed. They` may be mixed, and the mixture may be fedinto Ythe reaction chamber at one time or over a limited period of"time.' Or if desired, one-half ofthe fluoride may be mixed with all ofthe titanium-bearing material and this mixture charged into the furnaceas described. After this charge has reacted the balance of the ammoniumfluoride isadded over 7 for example, as previously mentioned, higherreaction temperatures are required for rutile than for ilmenite. Inanother variation the ore and fluoride are thoroughly mixed cold,briquetted and then heated in the reaction chamber, thereby minimizingthedusting which may occur as a A result of the evolution of vaporsduring reaction, for example, of the titanium tetrafluoride compounds atabove 290300 C. 'Thorough mixingof the uoride and ore, as by grinding ina ball mill or edge runner, is conducive-to complete re-v `actionbetween the materials. The reaction mixture may also be prepared byadding the ammonium fluoride to the finelyI ground ore in the form of a4cor icentrated aqueous solution. The

water is then driven oif' and an intimate mixture In carrying out thedry way process, the reac- `tiofn mixture of, for example, ilmenite andammoniumfluoride may'be held at a reaction temperature below about 150C. until ammonia practically ceases to be evolved. The reactionnassbecomes a white or grayish white powder. The titanium compounds may thenbe separated by solution or leaching, or by volatilization. Thoseseparation methods also 'apply to the wet reaction process describedhereinafter. In either case it may be desirable to' preliminarilyVremove other volatilizable. compounds, such as ammonium ilioride orsilicon compounds. Thus the -temperature may` be raised and the volatilematerials drivenfronr the reaction As the heat is applied and thetemperature is raised, excess ammonium iiuoride and also .a part of theammonium fluoride compound formed `at the lower temperature arevolatilized. The higher temperature also Vtends to complete the reactionwith 4any titanium-bearing material which may.

'not have been .reacted upon previously. As the temperature is raisedabove 230o4 C., silica present is-vfolatilized as silicon diamminotetrafluoride, thisV compound being substantially entirely .volatilizedbelowx290 C. It may be condensed with the 'volatilized ammoniumjuoride.Al-

though the temperature of thefreaction mass may `bekent below 300? C.and above 150-200 C. for a period of .time'in order to volatilize asmuch ammonlumdiuoride as possible tjorseparate recovery thereof,it'usually is desirable to cut the operating time by raising thetemperature as rapidly as possible from 150 C. to above 300 C.

The titanium may be then separated from the reaction mass byvolatilization or by solution or leaching. Fortheivolatilizationof thetitanium tetrafluoride compound formed by the partial decomposition ofthe original complex compound at above about 150-290 C., a temperaturein excessof 290f300 C. is required,350f400 C. usuallyv being sumcient.The complex titanium te'traiiuoride compound is largely dissociated withrespect to the ammonium fluor-i nd vaporized as ammonium fluoride andtitanium tetrafluoride f compounds, principallyammino compounds such astitanium"dia'mino tetrauoride (TiF4.2NH3).

The FeF2.2NH4F also "dissociates, ammonium fluoride volatilizingandleaving the Airon fluoride.-

Thus, afterthe temperature of the reaction mass passes .300 C. there isan evolution of the diammino compound and possiblyV other ltetrafluoridecompounds. The temperature usually is increased to a maximum of about550 C., al-

though' higher temperatures 4may be used.

v. tures.

VI may use, as the reactive fluoride, either ammonium uoride or ammoniumbiuoride or a' reaction mixture capable of producing such uor' Y idecompounds such as a mixture of ammonium sulfate with a metallic fluoridesuch as nuorspar.V

use ammonium fluoride, and I prefer the normal K salt over the acidsalt.

The reaction residue, after removal of the titanium compounds byvolatilization at 350400 C., contains metallic iiuorides, such asuorides o iron, aluminum 'and the like,I and may contain someunvolatilized titanium yfluoride vcompounds such as titano-iiuoride,titanium oxyiuoride and the like. When these are heated to the highertemperatures, for example, 500 C. or higher, further dissociation and/orvolatilization of these compounds may occur and thereby further recoveryof volatilizable fluoride compounds effected. Ammonium titano-iuoride(NH4) z'IiFe, which may beformed in the various reactions, v olatilizesundecomposed at such higher temperaresidue may be eiectel also byheating the final residue in an atmosphere of water vapor and am- \monia(such as that formed in the primary re-V viuoric acid respectively; or areactive sulfate,

such as ammonium sulfate, may be admixed therewith and the mixtureheated to about 300 to 350" C. The titanium ores available usuallycontain considerableiron. This reactionoproduoes ammonium-fluoride whichpasses off as a vapor, ferrous sulfate and other metallic sulfatos,probably as in reaction (4) infra. The ferrous sulfate may bedecomposedin the usual way by roasting in the presence of steam to formsulfuricacid and iron oxide. If any nonevolatile titanium fluoridecompound is present in the reaction residue, it likewise is decomposedby the ammonium sulfate under these conditions, the titanium being atleast in part vaporized as an amminotetrauoride.

The ammonium fluoride produced in the sulfate reaction may beemployed inthe process as hereinafter described more in detail. Losses of ammoniumuoride which occur in the process maybe made up by adding the desiredamount of a mixture 'ofilucrspar and'ammonium sulfate? lor of otherreaction mixture capable of .forming ammonium uoride, to the reactionresidue during its` decomposition `by ammonium sulfate. i

-The volatilized compounds formed during the Removal of the' fluoridecontent' of the' operations described and which comprise tita-'f mmoniumtitano-iluorideand other compounds,

to a treatment which eifects solution of the ti- `umdiamminotetrauoride,ammonium fluoride, Y

Y may be condensed and collected for treatment tanium -compounds orwhich directly precipitates the-titanium las hydrate. `.Suchprecipitation may be e'ected by reacting upon the titanium compoundsiAther in vapor form or after condensation as -aY solid, with water andammonia. The ammonia shouldA be used in excess.

The hydrated titania is denser-if an ammoniaca] solution of concentratedammonium fluoride is used for the reaction, and especially if thissolution is cold y(below 34 C. and preferably below C.) when it contactswiththe titaniumtetrafluoride compounds. As'set forth hereinafter, undercertain conditions of concentration a crystalline -salt of titaniuminstead of the hydrate A forms.

the solution may vary widely, and may be from 16% to 50% or higher. lIprefer to use a concentration of from 20% to 40% when producing thecrystal product as hereinafter set forth. The diamm'inotetrafiuoride andother volatilized com- 'pounds may either be condensed as a. powder anddissolved or the vapors may be contacted directly with the fluoridesolution, suitably in a spray chamber or countercurrent gas-washingtower. In addition to the titanium compounds, ammonium fluoride and anyother accompanying soluble salts aredissolved. The inal concentration oftitanium salts in the ammonium fluoride solution which it is desirableto obtain is indicated hereinafter. The resultant liquor also retainsthose solids which may. have been carried over mechanically from` thereaction fur" nace in the form of dust. Iron fluoride and other heavymetal compounds which are carried over either mechanically or in vaporform are dissolved, to the extent of their slight solubility by theammonium fluoride solution. The iron and other heavy metals must beremoved quantitatively if a white titanium vdioxide pigment is to beproduced.

I have found that it is possible to remove substantially quantitativelythe iron and-other heavy metals dissolved in ammonium fluoridesolutions, containing titanium tetrafluoride compounds dissolved thereinby treatment with a soluble sulfide, without simultaneouslyprecipitating the titanium. The hydrogen ion concentration of thefluoride solution of the concentration noted above must be regulatedcarefully. The slightly acid fluoride solution may be neutralized withammonia to the point at which the addition of more ammonia precipitatesout permanently the hydrate or a crystalline titanium compound. Thispoint is designated as substantially neutral for convenience hereafter.

After this condition is attained, ammonium sulfide is a convenientsoluble sulfide which may be used as the precipitant. Sodium orpotassium sulides or hydrogen sulfide are other soluble sulfides thatmay be used. If hydrogen sulfide is used, additional alkali is requiredto maintain the necessary neutrality. The iron .and other heavy metalsareprecipitated as sulfides either ina hot or cold solution, a hotsolution (about '10 C.) being preferred. The precipitate may be filteredreadily from the solution together' with any other insolubles that maybe present. The iron sulfide is precipitated as the ferrous salt, theammonium sulfide reducing any ferrie salts to the ferrous condition.Precautions must be taken to prevent the ferrous sulfide, before it is'separated from the solution, from being again oxidized to the ferriecondition whereby it will again dissolve inthe fluoride solution.

The titanium*may be largely or completely separ'ated from ther. reactionmass resulting from 5 the ltreatment of the Atitanium-bearing materialwith ammonium fluoride as above described (prior to dissociationv andvolatilization ofthe titanium compounds therein) by leaching the sam'ewithanon-alkaline aqueous liquid. Thus, a solution 'of` the naturehereinbefore described, containing` the titanium diamminotetrauoride andotherktitanium salts'y dissolved therein may be obtained.;'Whenthereaction mass formed as above des.rib'ed,"by4 reaction on the titanium-15 bearing material with ammonium fluoride at temperatures below about150 C.. or at higher temperatures to about 290 C.-300 C.,- is leachedwith an aqueous ammonium -fluoride solution (either hot or cold, neutralor slightly acid) of the concentration hereinbefore described fordissolving the volatilized titaniumtetrafluoride compounds, a solutionis formed which is similar in its properties and is apparently the samevor equivalent in behavior to that formed when the volatilizedvtitaniumcompounds are dissolved in the ammonium fluoride solution. In someinstances there may be excess ammonium fluoride lin the reaction masssufficient to provide part or all of the requirement of the leachingsolution and water or dilute ammonium fluoride solution may be usedaccordingly. This solution secured by leaching, which may also containsmall amounts of dissolved iron, may then be treated for removal ofiron'while either `hot or cold by 35 a soluble sulfide 'and filtered aspreviously de- The leaching process described in the preceding paragraphmaybe used advantageously when rutile is the ytitanium-bearing ore. Thesmall 40 amount of iron contained in rutile as an impurity leaves but asmall amount of insoluble residue, thereby minimizing the leachingproblems and costs.

In carrying out the decomposition reaction in the wet way it ispreferred to use a larger excess of ammonium fluoride or equivalentbifiuoride than in thedry way reaction (Equation 3).; say, in excess of12 molecular parts. For example, 4 parts by weight (about `16 molecularparts) of NH4F is found desirable for 1 part of ilmenite. As in the dryway" reaction with ammonium fluoride, finer grinding of the ilmenitealso increases the emciency of the reaction as deter'- mined by thetitaniumA dissolved. Water may 5, be added to a mixture of ammoniumfluoride and the titanium-bearing material. Preferably, the ammoniumiiuoride is added to the nely ground titanium oxide-bearing material inthe form of a solution, preferably concentrated, and the mixture heated,preferably with stirring. As the temperature is raised the solutionattacks the titanium-bearing material and a pasty mass is formed, .thetemperature usually reaching above 150 C. 'I'here is a vigorousevolution of ammonia and the pasty mass becomes gray in color as thereaction proceeds. Althoughthe reaction is substantiallycomplete at-150" C. in the presence of water in the reaction mass, the temperaturemay be increased to above C.

After the reaction is complete the titanium may be volatilized byheating the mass to above 290- 300 C. and preferably to about 500-550 C.to volatilize substantially all of the" titanium as tetrafluoridecompounds. I prefer however to 75 .leach the mass with an' water or anaqueous solution of ammonium fluaqueous fluid, such as oride. The amountof excess ammonium fluoride in the reaction mass usually is suilicientso that additional ammonium uoride is not used in the leaching water inorder to provide the best cone ditions for precipitating thel heavymetal suldes and securing decreased iron fluoride solubility asexplained hereinbefore. 'I'he reaction mass is The dissolved titanium Yleached with water. tetrailuoride salts, probably double fluorides, are

. flltered from the insoluble portion, which consists largely offerrousammonium 4fluoride if ilmenite is the titanium oxide-bearing rawmaterial. The residue is washed with water or ammonium uoride solutionto remove the soluble titanium salts. The residue may then be heatedreaction is -lpreferably carried titanium may be in a retort inthe'presence of oxygen or air and steam A.-to volatilize and regyer theammonium fluoride and convert the ie ous fluoride into an iron oxide andhydrofluoric acid which may be neutralized with ammonia to produceammonium uoride. VThe iron oxide so formed is a finely divided iluifymaterial, of value as a paint pigment.

The solution of the titanium double salt is neutralized with ammonia tothe correct hydrogen ion concentration for treatment with a solublesulfide for. the removal of iron and other heavy metals, as described inthe dry way process. The iron is removed as a sulde and the titaniumsolution treated as described hereinafter for the production of oxide. YRutile may be used in place oi ilmenite as the raw titanium-bearingmateri l. A larger proportion of ammonium fiuorideis used and theinitial out at a slightly higher temperature, say about 150 C. sincerutile is less easily attacked. Since rutile contains little iron oxidethe residue does lnot present a recovery problem as when ilmenite isused.

=..A solution of titanium compounds may thus be secured by solution oftitanium fluoride com# pounds volatilized from a suitable reaction mix-vture, by solution from such a reaction mixture, orr by direct reactionon the titanium ore in the presence of a suitable solvent. The filteredammonium fluoride solution free from iron and other heavy metals andcontaining the titanium o diammino-tetrauoride or other titaniumtetrauorlde compounds dissolved therein is then subjected to the actionof ammonia for the precipitation and separatzon of the titanium. Withmore dilute solutions the hydrate may be produced and vafter ltsVremoval the solution concentrated and returned to the system. To .securea crystal procl-l uc't as hereinafter set forth, anhydrous ammonia maybe passed into the solution, and the solution also may be cooled toobtain the optimum yield oi' the crystals as -set forth hereinafter. The

tatively under the star-like in shape, which seem to have-the'approximate composition 'IiF4.2NH3.NI-I4F, and ap-. parently. do notcontain any water of crystallization. The crystals are removed and themother liquor, which is an ammoniacal strong ammonium fluoride solution,is returned'to the process.

v-The formation ofthev octahedral crystalsvby adding ammonia to thesolutionof theL titanium fluoride compound takes place under conditionspreferably controlled as 'to the percentage of total solids(NH4F`+TiF4-) in solution and as tothe ratio of NH4F to TIF; in thesesolids. The most 'tals are preferred to the precipitated practicallyquanticonditions hereinafter set forth inf the form of definiteoctahedralcrystals, often` 5 favorable' condition fr the formation ofthese crystalsl appears to be within the limiting NIERF to TiF4 ratiosof 21/2 Y Within these ratios the crystals start to form. at a totalsolids concentration of a little better than 20% or an NH4Fconcentration of at least about 16%, the optimum being at about theratio of 3 to 1 by weight. If the ratio is decreased or increased ahigher totalv solids concentration is needed to form the crystals. Forexample,- at the ratios 1.6 to 1 and 4.8 to 1 a total solidsconcentration of 40% is needed to precipitate the titani- 'umtetrauoride compound in the form of the Outside of the limits necessaryfor producing the octahedral crystals either 'crystals of other typesare formed, some of which are long, thin and needle-like or the hydrateis formed. I'he needle-like crystals are bulky and are more dicult tohandle and therefore the octahedral crys- The hydrate produced directlyby the addition of ammonia to the solution may be used to produce ahighly satisfactory pigment.

It has been found, that under the preferred` favorable conditions oftotal solids concentration and ratios of NH4F the octahedral crystalsmay be precipitated by the addition of ammonia water to the ammoniumfluoride solution of the titanium tetrai-luoride compounds, while underless favorable conditions'. anhydrous ammonia is needed for theprecipitation.` These conditions are explained by the-data given above.k

The titanium ammino-ammonium uoride compound which volatilizes at about400 C.

crystallizes at times as well dened octahedra,

but as a rule star-like crystals are developed by twinning. For example,a solution of the followd ing composition gives excellent results: TlF4,11.5% (as calculated from Ti content), and the remaining F calculated asNH4F=27.0%.

'111e procedure for the separation of the titanium iiuoride compound maybe varied. Flor example, the hot concentrated non-alkaline ammoniumfluoride solution containing `the dis- Asolved titanium (uoridecompounds) may -be cooled before removing the iron and allowed tocrystallize. The crystals so formed are irregularly shaped and somewhatpoorly dened. FI'hey are separated from the mother liquor, dissolved ionconcentration regulated to neutrality, and a to TiFr' previously setforth.

'in a limited amount of hotwater, the hydrogen hedral type crystals ashereinbefore described.

are desired.

The crystals of complex titanium salt jected to the action of water andammonia to produce the hydrate. I prefer to carry out vthis reaction intwo steps. l'In the preferred method A the crystals are rst treatedwitha limited measured amount of water, preferably fromV 1 to 2 timesthe weight of the dry Crystals. 'If the water is addedVA at on'e timethemixture rst thickens andsets into acheesy mass, but o :further stirjring, which sliould'be more oi' the nature of a grinding action, "theiltitl'V pasty mass greatly byfthe method of adding Even after "dryingat 110,C.

more iluid. I meten-however, to add the water slowly with constantstirring to the crystals.

u About one to twoA parts of ammonia water are now added to the watersuspension previously produced. The physical properties ofthe titaniumoxide pigment produced .are affected the water and ammonia, theconcentration of the ammonia,

and the temperature. The resultant mixture isthe hydration product issoluble in weak HC1 The titanium oxide may then higher temperatures upto 900-1200 C. to impart various properties demanded by the paintindustry. i The pigment thus made is of extreme whiteness and has highopacity and hiding power.

In another variation of my procedure, the digested mass resulting fromthe action of ammonium iluoride on ilmenite or rutile is leached withhot water or hot ammonium .nuoride solution. The hot leach liquor istreated to remove iron and is then cooled without the further additionof ammonia. Crystals of a doublel salt of titanium and ammonium fluorideare formed which are treated with ammonia water to produce the hydrate.A

Although the preferr d vprocedure with the octahedral andstar-shapedcrystals is to form the hydrated oxide in two steps asdescribed. this process may be carried out, though with lesssatisfactory results, in one step proper concentration and amount ofwater to the crystals.

The hydrate, as previously noted, may be'produced also directly from theammonium fluor-A ide solution of thev titanium salt without iirstforming the star-shaped crystals.' This may be done by diluting thesolution and adding ammonia or adding the solution to ammonia water. Forexample, the titanium solution .previously referred to containing 11.5%of -TlF4 and 27.0% NH4F after removal of the iron is diluted with waterto 8.5% TiF4. and 20.0% NH4F. 'It is then poured into ammonia watercontaining NH3. This is about the upper limit of concentration of NI-LFto TiFq. (total solids) beyond ammonia which crystal formation takespla'ce at this particular ratio of NH4F to TlF4 (2.321) with thisparticular concentration of ammonia water. If stronger ammonia water is'used then the concentration of solids in the titanium solution shouldbe lower, and vice versa, if a weaker ammonia water is used a greaterconcentration of solids may be used. Ii the 20% ammonia waterl ispouredinto the titanium solution toproducethe hydrate, the concentrationV oftotal solids must be decreased below the 28.5% used above, preferablybelow 20%. In ge eral, it is desirable to keep the NH4F to TiF4 ratiobelow 3:1'. The hydrate so v.l'ormed is washed, dried and 4calcined aspreviously described. It isparticularly characterized by its highmobility. For example, a typical product formed as herein described hasa .described in Gardners metal or ammonium preferably is added to act astween the metallic compoundsV to reaction. A double fluoride compound oftitaniumv by adding the l by the mobilometer test Physical and ChemicalExamination of Paints, Varnishes, Colors 6th Ed., 1933) less than 10seconds;

mobility as determined for example, of about 4 seconds. Titanium oxidepigments as hitherto produced have much lower mobility, as indicated bymobilometer readings 'in general in the order of 20,: seconds andhigher.

A p igment with good covering .power may .be produced byadding ammoniadirectly to the dry condensed titanium diammino-tetrafluoride. Thediammino-tetrauoride must be of high purity and free from iron and heavymetals if a high grade product is to be produced by this method. Thediammino-tetrailuoride is freed conveniently from iron fluoride andtheir impurities mechanically carried over during the initialdecomposition reaction by resublimation.

By choosing as the titanium-containing mate- Lacquers and l rial ananhydrous titanium salt, such as an alkali- 20 double sulfate, and ametallic fluoride such as sodium fluoride as the iluorine source, thevaporization of the titanium as `a tetrafiuoride compound may beaccomplished as illustrated in Equation (5) z By heatingammonium-titanium sulfate with, for instance, calcium nuoride, uoride isformed and vapoized together with ammonium fluoride, as illustrated inEquation (6) If an alkali-metal double sulfate is used in the reactionas in Equation (5) ammonium fluoride an intermediary befacilitate theand ammonium is apparently primarily formed; Since titaniumtetrailuoride condenses to a liquid and is corrosive to metals it is.desirable to form `the non-corrosive diammino compound which condensesto asolid by carrying out reactions (5) and (6) in the presence oiammonia gas.

The temperature at which the reactions (5) and (6) take place is belowthe dissociation temperature of the titanium sulfate compound, andpreferably below about 400 C.

The present principal available sources of titanium oxide are ilmeniteand rutile. Rutile is less reactive than ilmenite and requires a higherdegree of pulverization. lreheating to 'above 140 C. withlsudden coolingincreases its reactivity.

The accompanying drawings are ilow sheets diagrammatically illustratingseveral embodiments of the invention.

The following are speciiic examples of methods for carrying out myinvention. l However, it is understood that my invention is not limitedto specific details thereof.

The handling of the reaction mixture in the heating oriurnacingoperation may be varied in accordance with the material treatedand the type of furnace used.

Thus, 100kilos of ilnely pulverlzed ilmenite, containing 52% TiOz and44% FeO (the iron pres-'- ent being calculated as FeO) i may beintimately mixed, suitably by means of an edge runner, with 300 kilos ofcentrifuged ammonium fluoride crystals, usually containing about 4% ofmoisture.

The mixture isied'v over a period oi time (20-to 60 minutes) into anenclosed, externally-heated furnace with suitable stirring mechanism,-feeding devices and outlets for discharge of the vapors and residue.'Ihe temperature of the material in the furnace is maintained at about110150 C.

In some cases, it may be desirable to maintain a temperature of'150 C.,and at times-it may be found desirableto go to somewhat highertemperatures. The selected temperature is maintained during the initialreaction period in which the metallic oxides react with the ammoniumfluoride, for/ming metallic fluorides, and ammonia and water arerformedand escape in gaseous form from the furnace. 'I'he time of reactionvaries with the depth of the charge in the furnace, a layer 6 inchesdeep requiring about 3 hours. The reaction is complete when no moreammonia is evolved.

'Ihe ammonia. is collected, suitably by absorption in water, or it maybe used for other reactions as hereinbefore described.

If a muille type f ture of ilmenite and ammonium fluoride, in the lsameproportions, after being intimately admixed, may be compressed inlayers-'say about 21/2 inches thick, in pans which are placed in thefurnace, provided with the necessary vapor outlets.

Rutile or `mixtures Vo1.' rutile and ilmenite may 1 be handled in asimilar manner and in similar proportions, the rutile being preferablysubjected to a preliminary calcining operation.

For example, 100 kilos of nely ground rutile are intimately admixed with450 kilos of ammonium uoride in an edge runner, charged into thefurnace, and heated to a temperature of 1506 to 170 C. until no moreammonia is evolved. The rutile may be prelminarily heated, if desired.

If desired; the charge of titanium-containing material may be fed tothe'furnace with only a part of the ammonium fluoride, the remainderbeing supplied later. Thus, a finely ground mixture of 50 kilosof rutilewith 50 kilos of ilmenite is mixed with 120 kilos ofl ammonium fluorideand heated at about 170" C.' If desired, 25 kilos or inert material,such as uorspar or the iron fluoride residue obtained as hereinafterdescribed,

is mixed with the charge toprevent caking. .After an hours heating,another 120l kilos Vof ammonium uoride is fed into the furnace, andanother 120 kilos after two hours of heating. The charge is maintainedat the initial temperature until the @reaction is complete and no moream,

monia is evolved. After .the completion of the reaction by the' methodsand with the mixtures as set forth above the temperature of the reactionmass is raised to about 250 C., vapors of ammonium fluoride beingevolved'. Thereaction mass is kept at this temperature for a, suitableperiod, say, about an hour. Thesevapors evolved preferably are'eollectedseparately from the ammonia vapors previously evolved. If silicondlamminotetrauoride is evolved this also is collected. Forremoval oftitanium compounds by volatilization the temperature is now raised above300 C. the nal temperature being about 500 to 550 C. There is a'heavyevolution of vapors; principally titanium-diammino-tetrafiuoride andsome ammonium fluoride during the earlier stages. As the temperature israised,` the total time of heatingbeing, suitably inthe case d escribed,3`to 5 hours', the volume'ofvapors d creases, the iinal reactionmixture; after completion of the initial reaction as indicated by the'cessation of the evolution of ammonia, maybe rapidly heated to 500. to550 C., with evolution of vapors of ammonium fluoride, diamminonace is,employed, the mix fluoridev and titanofluoride hereinbeforev referredto.

'Ifhe vapors evolved may be collected and treated by passing them into aspray tower in which a hot (near-boiling) 2,0%40% ammonium fluoridesolution is circulated and in which the ammonium uoride (NHiF), titaniumuoride (TiFQ ratio is kept between 2,5 to 1 and 4 to 1. To do this,portionsA of the circulating liquor of the desired concentration aredrawn oi from time sulfide and other insolubles 'are filtered from thehot solution', whichl shouldl be substantially free from iron and heavymetals if a. white titanium oxide pigment is to be produced therefrom.The purified,'flltered solution is then treated with ammonia gas.Ofctahedral crystals, many of vwhich are star-like in form, are forl'nedand Substantially the separate from the solution. entire titaniumcontent of the solution separates l .therefrom in these crystals,especially if the solu- -tion is cooled to room temperature. The motherliquor is removed from the separated .crystals and contains ammoniumfluoride which may be recovered for treating further quantities of oreor the solution may be returned to the spray tower' after rst removingthe ammonia.

The crystals, whichl are voi the approximate compositionTiF4.2NI-I3.NH4F, are ltered or centrifuged to remove adhering motherliquor and are then hydrolyzed by the addition of 1 to 2 parts of watervin small portions while simultaneously subjecting the crystals to agrinding action. 'I'he hydrolyzed product has the consistency oi' athickened liquid..

One to two parts of strong ammonia waterare added to hydrate the\drolyzed product. v The precipitate Ais dense andthe fluid suspensionwhich results from the action of the ammonia filters readily. Ammoniawater is used to wash the hydrate on the lter to remove ammoniumfluoride. 'Ihe ammonia and ammonium fluoride in the ltrate are reused inthe process.

The 'lter cake of hydrated titanium oxide I containing ammonia water isdried and calcined at a temperature about 900 C. to 1100* C. The

titanium oxide produced thereby makes an excellent. pigment, and has thecharacteristics hereinbefore set forth. l

'I'he liron iiuoride residueain the furnace after volatillzation of thetitanium tetraiiugride compounds therefrom may be treated bypassingmoist air over it while it is maintained at substantially the sametemperature as is used during the volatilization of the titaniumcompounds. The hydrofluoric acid which is evolved is collected suitablyin ammonia water, thereby regenerating ammonium fluoride. The iron oxideformed may be used as a pigment. Y

' 'I'he vapors Vcontaining titanium tetrafluoride compound secured onheating the reaction mixture of titanium ore and ammonium fluoride atand above 300 C. after completion of the initial reaction, instead ofbeing' treated with water to dissolve the vaporized compound, aspreviously described, may be collected andrtreatedby pass- .ing intoa'spray tower in which is used or circulated an ammoniaca] aqueousliquor, preferably containing ammonium iiuoride in solution. If desiredall of the vapors evolved from thereachydrate is filtered out of theliquor and after gallons of 35% each 100 kilos of ore, y cold ormoderately the maximum concentration of ammonium fluoride has beenreached, a part of the liquor from the scrubber-,may be removed andfiltered, while the remainder of the liquor is recirculated with vtheaddition of the wash water from the titania precipitate to make `up theloss in volume. The ammonia and ammonium fluoride contained in thewithdrawn liquor are recovered for further use in the process.

The density of the' recovered titanium hydrateV may be further increasedby mechanical manipulation, for instance, by treatment of the filtercake in a ball mill. The recovered hydrate is dried and calcined a's'above described.

In the preceding specific procedures, the removal of titanium compounds'from the reaction mass has been effected by volatilizatiom They mayalso be removed by leaching or solution, asl has beenV hereinbefore setforth. The reaction is initiated as set forth above'in connection withspecific reaction mixtures and is carried to completion of thereaction"A in which ammonia is evolved, which may be at l50jf1'70 C. Thereaction mixture may then befsubiected to the-leach- -ing operationhereinafter described, or it may be heated to" a higher temperature, upto 250 C. as described above to effect removal of ammonium .iuoridebefore subjecting it to the leaching operation; or it may be carried toa higher temperature of 230- to 290 C. to also effect removal of silicaas silicon diamminotetrafiuoride before be' ing subjected to theleaching operation.

In` the leaching operation the charge is removed from the furnace, forexample, after volatilization of ammonium fluoride, or at a laterselected stage of reaction, and leached with ammonium fluoride solutionfor the solution being either heated, say to 65 C., preferably `usingcountercurrent circulation. The strong ammonium uoride solution is usedto minimize the solution of the iron fluoride. weaker solutions may beused, if desired, or if the reaction mass is leached before thetemperature isv raised to effect volatilization of ammonium fluoride.'I'he slurry is filtered and the filtrate treatas herein described. l

When the titanium-containing material is rutile alone, the small amountof residue remaining after volatilization of the titanium compounds orafter the leachingoperation may be again reacted with ammonium fluorideand leached in the same way.

The reaction residues may also be treated as follows:

The Vresidue remaining after leaching or the hot iron fluoride residuein the furnace after volatilization of the titaniumtetrafluoridecompounds therefrom is treated by adding ammonium sulfatethereto, and decomposed. Approximatelyl 0.8 part by weight of ammoniumsulfate for 1 part by weight of the original ore may be of roasting itas aboveset forth.

in the same manner as previously connection with the volatilizedtitanium fluoride added. The temperature during the decomposi- Y tion ofthe residue is preferably kept at about 30o-350 C. Ammonium fluoridepasses of! and iron sulfate is formed together with sulfates of metalsoccurring as impurities in the ore and remaining unvolatilized orundissolved in the reaction residues.

The furnace residue, consisting. almost entirely of ferrous sulfate, isroasted at atemperature .of above about 500 C. andsuifuric acidregenerated in a way known to the art. This acid may be combinedrwithammonia produced in the preceding operations to form ammonium sulfate,

which may be employed in a further dissociation of fluoride residue.

The iron is recovered as iron oxide. y r

The ammonium sulfate used in the operation also may be regenerated byreacting ammonia, evolved during treatment of the ore or produced duringother 'stages ofthe process, with iron sulfate, crystallized orinsolution, derived from the residue. 1

If desired the residue may -be leached for the production offerroussulfate, (copperas) instead If the titaniferousmaterial containssilica.,l 'a complete separation is' secured when the amf moniumfluoride is volatilized from the reaction mass at temperatures below 300C. The mixed ammonium fluoride and silicon diamminotetrafiuoride vaporsare treated or washed inany suitable device or scrubber with water-orwith a solution of ammonium fluoride as aboverdescribed.

which has not been made ammoniacal. I have named the silica which isthereby precipitated, alpha silica". This silica is filtered off and theltrate, containing the ammonium fluoride and ammonium silicofluorideresulting from the reaction between water and the silicon octetrailuoride is then treate'd withv ammonia. By 40 keeping thetemperature low (below 34 C. and preferably below 10 C.) during thistreatment with ammonia and keeping the solution concen-I trated a dense,opaque, silica, which Ihave named beta silica, is precipitated. Thealpha is translucent and has a high oil absorption and it is thereforedesirable to conduct -the operation in two steps as described. The beta"silica may be used to produce a silica-titanic pigmentjof high tintingstrength and hiding power, the silica acting as anextender though it has,considerable covering power in itself.

If desired, the mixture of and silicon tetrauoride'vapors,

ammonium fluoride vproduced as above described, are mixed with thetitaniumdi- 5 amminotetrafluoride vapors produced by heating a reactionmixture athigher temperatures. as previously set forth. This mixture iscontacted with a concentrated ammonium fluoride solution compounds. Thealp silica produced thereb y may be filtered from the solution priortothe removal of the iron as a sulfide as described or it. may beremoved to remove the iron. The presence of the "alpha" silica isdesirable because n solution. The ammonium siliofloridesremalning insolution subsequentlyreacts with the ammonia which is added to thefiltratev to thereby form the "beta silica. The titania is precipitatedwith this silica. Such a solution of titanium tetrafiuoride compoundsand ammonium silicovuoride is produced when the reaction mass is Yleached with ammonium iiuoride solution, when 75 described ino by thefiltering operation used 65' it helps to clarify' the be dissolved inthe solution of complex titanium Afluoride compounds in ammoniumfluoride solution after removal from the latter of the iron as sulphide,further water being added if necessary.

If desired, mixed titanium and silicon amminotetraiiuoride vapors may bedriven of.F om the reaction mixture by proper control of the tem'perature and, after removing dust mechanically carried over, contactedwith ammoniacal liquor or ammoniacal ammonium uoride solution asdescribed above in connection with the titanium vapors, to therebycompletely precipitate the titanium and silicon as a mixture of titam'aand .the alpha and beta silicas previously described. This mixture isthen ltered from the solution, washed and dried. It is calcined if apaint pigment is to be produced.

To secure a pigment product, ammonium silicouoride produced separatelymay be mixed with calcinedtitanium dioxide as produced as hereinbeforedescribed, for example, in the proportion of 9 parts by weight oi' (NH4)4:SiFs to 1 part by weight of TiOz. yThe ammonium silicofluoride may bein the form of crystals or in solution.

The beta silica is then precipitated by adding ammonia. 'Ihe precipitateis filtered, washed and calcined at 350 C. or at a higher temperature.'I'he resultant pigment has a high tinting strength and makes a paintwhich produces a smooth glossy finish on drying. Instead ofprecipitating thebeta silica onto the titanium dioxide, the silica maybe precipitated first and then mixed with 'the'titanium dioxide.

In one of the preceding specific examples,in connection with thetreatment of a reaction residue, the addition of-a mixture oi' uorsparand ammonium sulfate has been described to produce ammonium iiuorideneeded to make up deficiencies of that material. It is readily apparentthat inpany of the various modifications of the process, a similaraddition may be made for the same purpose to the reaction mixture beforetreatment,

.or to reaction residues which are to be subjected to further heating. y

The following examples illustrate operations in accordance with theinvention in which' water is present during the initial reactioninvolving the titanium-containing mixture:

100 kilos of finely ground ilmcnteare mixed with 400 kilos of ammoniumfluoride, the latter being dissolved to form a strong water solution.

' This mixture is introduced into a closed reaction vesselv providedwith a stirrer and the mass heated with* stirring. The temperature isAraised to -l80 C. and kept at the latter temperature with stirringuntil the reaction is complete, the ammonia, ammonium fluoride and watervapor formed by the reaction being vented from the vessel. The reactionmass is digested with hot water, the insoluble ferrous fluoride thenbeing iiltered hot from the leach liquor. 'I'he solution oi.'ammonium-titanium-tetrafluoride compound -is then neutralized withammonia and the.iron

removed with ammonium sulde while the solution is hot as in the case ofthe ammonium fluoride solution of the complex titaniumiiuoride compoundpreviously described. The resulti solution may be further treated forthe formionof 5 lthe complex titanium ammonium fluoride vcrystals or thehydrate as vhereinbefore set forth. It is preferred, however, tointroduce the ironfree solution, after dilution with water, into am:monia water to precipitate the hydrate. If the ammonia is poured intothe solution, some of the crystalline complex titanium-ammoniumfluoride" compound may form. The hydrate is ltered, washed free ofsalts, and calcined at 900 C. .The

titanium oxide which results has the character` istics of high mobility,previously seti'orthlff` The iron double iluoride residue is heated inthe presence of steam in a closed furnaceA tov 400-550 -C. 'I'hevolatilized ammonium biuoride formed is condensed and the residual ironoxide whichis formed may be used for pigment or abrasive purposes.'I'his makes a black pigment. If a red pigmentv is desired the doublefluoride is first decomposed at 40G-450 C. Whereby the ammonium fluorideis volatilized, leaving 25 the ferrous uoride, which is then treated at500.-550 C. with moist air.

When rutile is used as th`e titanium-containing material in theoperation last described, 100 kilos of nly ground rutile are Amixed with500 kilos of 30 ammonium uoride as a strong water solution thereof.'I'he mixturej is introduced into the reaction vessel and heated atabout-1'80 C. until the'reaction is completed. The reaction vmass isleached, filtered, and the solution of titanium tetraiiuoride saltstreated as in the op- 4 eration described, using ilmenite.

'Ilielterms "volatile and non-volatile are herein used to designatethose properties-at the temperatures involved.

In this appli ation I make no distinction between ammoni uoride andammonium bifluoride in their chemical -reaction with the ti taniumoxygen compounds. However, physically the two compounds dier, thebiuoride melting 45 and causing furnace diiiiculties not encounteredwith the normal salt. Likewise `the bisulphate of ammonia may be usedin-place of the normal sulfate. i t y. Y

In the various reactions ammonia and am- 50 monium fluoride are producedand consumed. It :isA understoodv that the process is cyclic withreference to these two materials, that is, when they are produced as aresult of .a reaction they are :recoveredmand used again in the process.necessary to make up for mechanical losses of these materials from timeto time. In certain reactions ammonium sulfate is the reactive material.The process with reference to this salt also is cyclic. In using theterm ammonium-titanium-uoride compounds herein, I vinclude thereunderboth amino and ammonium compounds lo/f the character hereinbefo're setforth. l

Where a non-alkaline solution is referred toin the claims this refers tosolutions in which the alkalinity is insuilicient to precipitate thetitanium as hydrate or crystals of the titanium amminotetraiiuoridecompound hereinbefore described. 70 A neutral solution of the titaniumtetrafluoride compound is one in which the addition of smallamminotetrauoride compound. 75

`of ammonium iluoride, the ammonium fluoride in such solution being insuch amounts as to provide a ratio of NH4F to TiFt of from 1:1 to 5:1 byweight.

3. In the production of titanium products from titanium-bearingmaterials, forming an yammonium-titanium iluoride compound and effectingsolution thereof in a non-alkaline solution of ammonium iluoride, theammonium iluoride in such solution being in such amounts as to provide aratio of NHiF to TiF4 of from 2.5:1-to 4:1 by weight.

4. In the production of titanium products fromI titanium-bearingmaterials, effecting solution of an ammonium-titanium-fluoridecompound/ln a non-alkaline solution containing ammonium fluoride, andmixing ammonia therewith, in quantity to eect precipitation of titaniumcompounds therefrom.

5. In the production of titanium products from titanium-bearingmaterials, effecting solution of an ammonium-titanium iluoride compoundin a non-alkaline solution containing ammonium iluoride, ammoniumiluoride being supplied in said solution to provide`a ratio of NH4F toTiF4 of from 1:1 to 5:1 by weight with a total solid cont tent aboveabout 20% and mixing ammonia therewith, thereby precipitating acrystalline ammonium ammino titanium fluoride there- 40 from.

l6. In the production of ltitanium products from titanium-bearingmaterials, effecting solution of an ammonium-titanium-uoride com.

pound in a non-alkaline solution containing ammonium fluoride, ammoniumliluoride being supplied in said solution to provide a ratio of NHtF toTiF4 of from 2.5: 1 to 4:1 by weight with a total solid content aboveabout 20% and mixing ammonia therewith, therebyV precipitating acrystalline ammonium ammino titanium iluoride therefrom. 1

7. In the .production of titanium products from titanium-bearingmaterials, effecting solution of an ammonium-titanium-iiuoride compoundin a non-alkaline solution containing ammonium uoride and mixing ammoniatherewith. the proportion of. ammonium iiuoride and of solids thereinbeing controlled to effect presolution thereof is eiected innon-alkaline solution of ammonium fluoride in such concentrations that acrystalline compound is formed upon the addition of ammonia to a neutralsolution thereammonium titanium iluoride y aoass of. the mthod o:precipitating a titanium hydrate from said ammonium-titanium-fluoridesolution which comprises mixing ammonia therewith so that anexcess ofammonia is present at the moment reaction occurs-between the titaniumsalt and ammonia.

10. In the production of titanium products from titanium-bearingmaterials, whereby an compound is formed and solution thereof iseffected in nonalkaline solution of ammonium fluoride in suchconcentrations that a crystalline compound is formed upon theaddition ofammonia to a neutral solution thereof, the method of precipitating atitanium hydrate from said ammonium-titanium-fluoride solution whichcomprises adding the solution of titanium salt to ammonium hydrate inexcess.

1l. In the treatment and purification of titanium compounds, effectingsolution of a titanium uoride compound in a non-alkaline aqueous liquidcontaining ammonium fluoride, neutralizing said solution and adding asoluble sulphide thereto, thereby precipitating dissolved heavy metalstherefrom.

12. In the treatment and purification of titani` um compounds, effectingsolution of titanium iluoride compounds in a non-alkaline aqueousliquid, supplying ammonium fluoride therein, adding ammonia rto saidsolution to bring it to a sub-I stantially neutral state and adding asoluble sulde thereto,thereby precipitating dissolved heavy metalstherefrom. t

13. In the treatmentY and purification of ti.- tanium compounds,effecting solution of titanium. iiuoride compounds in a non-alkalineaqueous liquid, supplying ammonium uqride therein to 1;'1 to 5:1 byweight,l adding ammonia to said solution to bring it to a substantiallyneutral state and adding ammonium sulilde thereto,y therebyprecipitating dissolved heavy metals therefrom. v

14. In the treatment and purification of titanium compounds, eilectingsolution of titanium iluoride compounds in a non-alkaline aqueousliquid, supplying ammonium fluoride therein to providetherein a ratio ofNHlFzTiFi of from 1:1 to 5:1 by weight and maintaining the totalcombined proportion of said uorides in said solution above about 20%,'adding ammonia to said solution to bring it to a substantially neutralstate and adding ammonium sulfide thereto,

thereby precipitating dissolved heavy metals therefrom.

15. In the preparation of puried titanium compounds, adding a solublesulfide to a substantially neutral solution of'ammoniim and titaniumiluorides, thereby precipitating dissolved iron therefrom, andsubsequently mixing ammonia with said solution, thereby precipitatingsubstantially iron-free titanium compounds therefrom.

16. In the preparation of purifiedtitanium compounds, adding a solublesulfide to'a substantially neutral aqueous solution of ammonium andtitanium i'luorides, thereby precipitating dissolved iron therefrom, andsubsequently mixing ammonia with said solution, the conditions thereofbeing controlled to effect precipitation of substantially iron-freetitanium hydrate therefrom.

17'." In the preparation of purified titanium compounds, adding ammoniumsulfide to a substantially neutral aqueous solution of ammonium andtitanium fluorides wherein the ratio of NHtF tetrailuoride with 1 to 2parts by weight of water, stirring the mixture whereby the liquidity ofthe to Tim is from 1:1 to 5:1 by weight-thereby precipitating dissolvediron therefrom, and subsequently adding ammonia, to the solution,thereby precipitating a substantially iron-free crystallineV'ammonia-titaniumuoride compound therefrom.

18. In the preparation of purified titanium compounds, effectingsolution of titanium fluoride compounds in an aqueous liquid, supplyingammonium fluoride therein, adding ammonia to the solution to bring it tosubstantial neutrality, adding a solublesulilde to said solution toprecipitate dissolved iron therefrom, and subsequently mixing ammoniawith said solution' to precipitateiron-free titanium compoundstherefrom.

19. In the preparation of purified titanium compounds, eiiectingsolution of titanium iiuoride compounds in an aqueous liquid, supplyingammonium uoride therein, adding ammonia toV the vsolution to bring it tosubstantial neutrality, add- `ing a soluble sulde to said solution toprecipitate dissolved iron therefrom, and subsequently mixing ammoniawith said solution under con'- ditions to precipitate iron-free titaniumhydrate therefrom.'

20. In the preparation of puried titanium i compounds, eiecting solutionof titanium iiuoride compounds in an aqueous liquid, supplying ammoniumiiuoride therein to provide therein a ratio of NH4F to TiF4 of from 1:1.to 5:1 by weight, adding ammonia to the solution to bring it tosubstantial neutrality, addingv ammonium sulfide to said solution toprecipitate dissolved iron therefrom, Aand subsequently adding ammoniato Isaid solutionto precipitate iron-free crystallineammonium-ammino-titanium fluoride compounds therefrom.

21. In the production of titanium products from titanium-bearingmaterials, eiecting solution of an ammonium-titanium-iluoride compoundin a non-alkaline solution containing ammonium iiuor'ide, neutralizingsaid solution, re

moving iron from said solutionand adding am' monia to the puriedsolution to precipitate titanium hydrate under such conditions thatexcess ammonia is present throughout said precipi tation reaction. v

N22. In the production of titanium products from titanium-bearingmaterials, eii'ecting solution of an ammonium-titanium-fluoride compoundin a non-alkaline solution containing ammonium iiuoride, neutralizingsaid solution and adding a soluble sulphide thereto, removing theinsolubles and adding ammonia to the purifled solution to precipitatethe hydrate under such conditions that` excess ammonia is presentthroughout s aid precipitation reaction.

23. The .methddof producing a hydrated titanium compound which comprises-subjecting an ammonium uoridetitanium-ammino-tetrafluoride compound tothe action of water and ammonia.

24. The method of producing a hydrated titanium compound whichYcomprises subjecting an ammonium Vfluoridetitanium-ammino-tetrailu- 25,The method of producing a hydrated ti- .Y

tanium compound which comprises subjecting ammoniumfluoride-titanium-amminotetrailuoride crystals to the action of waterand ammonia.

26. The method of producing a hydrated titanium compound which comprisesmixing crystalline' ammonium iiuoride-titanium-ammino- 'metal suliide.

ide compound, and treating said compound with water and ammonia.

28. In the production of a hydrated titanium oxide, [effecting solutionof titanium-uorine compoundsin a non-alkaline aqueous solution ofammonium uoride, adding' ammonia to the solution to effect precipitationof a complex ammonium-ammino-titanium iluoride compound, and treatingsaid compound with water and ammonia.

29. The method of producing a hydrated titanium oxide which comprisessubjecting a titanium oxide-bearing material to the action of ammoniumiiuoride to form ammonium-titanium-iiuoride compounds and effectingsolution thereof in a non-alkaline aqueous liquid, ammonium iluoridebeing supplied in the mixture ,in'excesa separating the resultingsolution, adding ammonia Ythereto to eifect precipitation of a complexammonium-amminoetitanium fluoride compound, and treating saidl compoundwith water and ammonia. i

30. The method of producing a hydrated titanium oxide which comprisessubjecting a titanium oxide which .comprises subjecting -a titaf mumoxide-bearing material mme action of a solution of ammonium fluoridecontaining an excess of ammonium iluoride at an elevated tem--perature,"dissolving the soluble constituents of the reaction mass inwater to form a non-alka-v line solution of a soluble ammonium titaniumcompound andi ammonium rfluoride, removing iron from said solution andreactingupon said solution with ammonia under such conditions that.titanium hydrate is precipitated.

32. Themethod of producing a solution of 4a l compound of titanium freefrom heavy metals, suchas iron, which comprises subjecting a titaniumoxide-bearing material to the action of a solution of ammonium fluoridecontaining an excess of ammonium fluoride at an elevated temperature,dissolving the soluble constituents of the reaction mixture, adjustingthe solution to substantial neutrality, adding a soluble sulcle to saidsolution and removing precipitated heavy 33. The method of producing atitanium hydrate free from heavy metals, such as iron, which comprisessubjecting a titanium ,oxide-bearing material to the action of asolution of ammonium fluoride containing an excess of 'ammonium iluorideatan elevated temperature, dissolving the soluble constituentsof thereaction mixture, adjusting` the solution to substantial neutrality,adding a soluble sulde to said solutionV and removing precipitated heavymetal sulde, diluting and reacting upon said solution with an alkaliunder such conditions that titanium hydrate is precipitated.

34. The method for producing an iron-free solution of a compound oftitanium from a titanium oxide compound containing -a heavy metal, suchas iron, as an impurity, which comprises mixing said compound withammonium fluoride, heating said mixture to volatilize titaniumtetrauoride compounds therefrom, contacting said volatilized titaniumcompounds and accompanying impurities with ammonium fluoride solution,adjusting the solution to substantial neutrality, adding a solublesulfide to said solution and filtering oiI therefrom any insolublesulphide formed.

35.. The method for producing an iron-free solution of a compound oftitanium from a titanium oxide ore containing ilmenite, whl h comprisesmixing said compound with an e `cess of ammonium fluoride, heating saidmixture to volatilize titanium tetrailuoride compounds therefrom,contacting the volatile titanium compounds and accompanying impuritieswith a hot strong ammonium iiuoride solution, regulating the hydrogenion concentration o! said solution, adding ammonium sulphide to saidsolution while hot,

and filtering oi the insoluble portion.

36. 'Ihe method for producing an iron-free solution of a titaniumcompound from a titanium in said solution with-a soluble sulphide, andrev moving the insolubles from said solution.

37. In the production of titanium products, the method for forming avolatile titanium compound from an oxygen compound thereof andseparating said volatile compound from any nonvolatile portion, whichcomprises mixing ammonium fiuoride with said compound and heating enoughto effect, the reaction between said titanium, oxygen compound and saidammonium iiuoride, and a later stage being above said rst temperaturerange.

' 38. 'I'he method of claim 37 in which the titaniu'm oxygen compound isilmenite and the upper temperature limit of said earlier heating stageis about 150 C 39. In the production of titanium products,- subjecting.a titanium oxide-bearing material to the action of ammonium fluorideunder reacting conditions and effecting solution of the resultingtitanium fluoride compounds in a non-alkaline aqueous liquid, providingin the resulting solution l an excess of ammonium fluoride.

tion an excess of ammonium :liuoride to give a ratio of NH4F toTiFytherein of, from 1:1 to 5:1 by weight v41. In the' production oftitaniumv products subjecting a titanium oxide-bearing material to theaction of an excess' of ammonium under reacting conditions, andeffecting lution of the resulting titanium fluoride compounds inl 'anon-alkaline aqueous liquid, the excess o! ammonium fluoride beingcontrolled to give a ratio of NHAF to Tim in said solution of from 1:1to 5:1 by weight.

42. In' the production of titanium products, subjectlnga titaniumoxide-bearing material to the action oi an excess of ammonium fluorideunder reacting conditions, and eiecting solution of the resultingtitanium fluoride compounds in a non-'alkaline aqueous liquid, theexcess o! ammonium fluoride and the liquid being controlled to provideat least 16% of ammonium uoride in the resulting solution. A l -20 43.Inthe production oi.' titanium products, mixing the pulverized titaniumoxide-bearing material with a substantial excess of ammonium fluoride inthe presence .of water suiilcient to dissolve at least a partoi saidammonium iluoride, heating said mixture to drive ofi' a substantialportion of said water and until the titanium oxide has reacted in largepart with said iluoride. 44. The method for producing a substantially.iron-free hydrate oi' titanium from an ilmenite so ore oi'titanium,which comprises treating saidy ore with ammonium iiuoride at elevatedtemper-' atures, the conditions ot reactiori andthe amolmt ofammoniumfluoride used being such that substantially all of the titaniumpresent in said ore is converted into a water soluble 'uoride salt andsubstantially all ofthe iron present in said ore is converted into adouble fluoride salt of iron and ammonium substantially insoluble inwater, said reaction being carriedout at va. temperature low enough toprevent volatilization of said titanium iihcride compounds, leaching thereaction product with water, removing iron impurity remaining in saidleach liquor and racti'ng said leach liquor with ammonium under suchconditions that a hydrate is produced.

45. The cyclical process for treating titaniumbearing ores containingsubstantial quantities of iron -which comprises heating said ore withamo monium fluoride in the presence o1' water and continuing suchheating ilntil the reaction is coml pleted without appreciablevolatiliaatlon of the fluoride formed by the reaction, leaching theresulting reaction product with water, treating the soluble portion withammonia formed in the in-l itial reaction under such conditions thattitanium hydrate laici-med, separatingfthe residual liquorcontainingjimmonium iiuoride from said hydrate, heating the' residuefrom the rst leaching operation and containing iron ammonium uo'ride tca temperature sumcient to volatilize ammonium fluoride from said doubleiiuoride, heating the residual iron fluoride with steam and air atelevated temperatures to form iron oxide and hydrofluoric acid,contacting said hydrofluorjc acid with ammonia formed in said initialreaction to thereby form ammonium fluoride, and treating furtherquantities of ore with said recovered ammonium fluoride.' l i svEND s.sVENDsEN. 70

oride 5

